Self locking box



April 1965 R. E. REEVES ETAL 3,178,096

SELFLOCKING BOX Filed June 22, 1964 2 Sheets-Sheet l Hi1? M3I I r v Q [Elm INVENTORS. ROBERT E. REEVES and BY HAROLD V. JoNEs,JR.

AHarnm s R. E. REEVES ETAL April 13, 1965 SELF LOCKING BOX Filed June 22, 1964 2 Sheets-Sheet 2 E II a III'IIII INVENTORS. ROBERT E. REEvEs and HARom V. JONES.JR.

wmmwz AHor United States Patent Ofiice 3,178,996 SELF LOCKING BQX Robert E. Reeves and Harold V. Foues, In, Indianapolis,

Ind., assignors to Inland Container Corporation, Indianapolis, 11111., a corporation of Indiana Filed June 22, 1964, Ser. No. 376,777 Claims. (Cl. 2Z939) This invention relates generally to fibreboard boxes and more particularly to a box wherein the flap construction is such that the bottom of the box can be closed and locked securely without the use of stitching, tape, rivets, or other types of fastening means.

Self locking boxes are already known in the container art.- However, those presently known have several disadvantages including: difiicult set-up, vulnerability to pilferage, weakness, and excessive material requirements.

It is, therefore, a general object of the present invention to provide an improved self locking box.

A further object is to provide a self locking box construction requiring no more fibreboard than conventional regular slotted cartons, and which can be set up quickly and easily, even if set up manually.

A further object is to provide a box achieving the foregoing objects and which is stronger and less subject to tampering and pilferage than are conventional self locking boxes.

Described briefly, a typical embodiment of the present invention is formed from a box blank having alternate side forming and end forming panels separated from each other by score lines. At the bottom of each side forming panel is a score line, below which is a bottom forming flap is provided, the flap being integral with the side panel. At the bottom of each of the end panels and separated therefrom by a score line is a bottom forming end flap.

Each of the end flaps has a pair of slots diverging from a centrally located lower marginal edge of the flap, each of the slots making a 45 angle with the lower marginal edge. Each of the side flaps has a notch in each of its side marginal edges, each notch beginning at the intersection of two of the panel and flap defining score lines and extending at an angle to a point approximately onehalf the distance between the flap defining score line and the lower marginal edge. The notch border then extends away from this point at a 90 angle with respect to the first portion of the notch and terminates near the lower marginal edge of the side flap.

In this way there are formed in each of the side flaps two cars pointing in opposite directions which are re- I ceivable in the slots of the end flaps, the slots and the ears being deep enough to accommodate complete closure of the flaps after they are inwardly folded and interlocked with each other. The interlocked flaps disposed in a plane perpendicular to the side and end panels of the box form the bottom of the box.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

FIG. 1 is a view showing the layout of the box blank employed in a typical embodiment of the invention.

FIG. 2 shows the box partially set up, with the interlocking of the side and end flaps beginning, the next step being to move the side and end flaps down to complete the closing of the bottom of the box and the interlocking of the flaps.

FIG. 3 is a view of the bottom of the box looking into the box after the bottom has been closed.

FIG. 4 is a view showing the outside appearance of the bottom of the box when the bottom has been closed.

3,178,095 Patented Apr. 13, 1965 FIG. 5 is a view of the blank employed in an improved embodiment of the box of the present invention.

FIG. 6 is a view of the bottom of the box as seen from the interior of the box after the bottom has been closed.

FIG. 7 is a view of the bottom of the box showing the outside appearance thereof after the bottom has been closed.

Referring now to the drawings in detail, and particularly FIG. 1 thereof, the box blank, which is usually made of fibreboard, and corrugated fibreboard if required, by the intended use of the box, has the side form ing panels 55 and 57 and the end forming panels 58 and 59 which, when the box is set up as shown in FIG. 2, form the box side and end walls. The dotted lines in FIG. 1 represent score lines and the flaps 61 and 62, while of material integral with the side and end forming panels, are separated therefrom by score lines. The same is true of the bottom forming end flaps 63 and 64. The top forming flaps i2, '73, 74-, and 76 may be formed in the usual manner for a regular slotted carton, as shown, if desired.

To provide the interlocking relationship between the bottom forming side and end flaps, the end flaps are provided with slots therein and the side flaps are provided with ears receivable in the slots. For example, flap 64 is provided with the slots 6 and 68, both of which diverge 5mm 21 point 76 colinear with the lower marginal edge 64a of the flap 64- and equidistant between the opposite ends or lateral marginal edges 64b and 640 of the flap 64. Each of these slots is disposed at an acute angle with respect to the lower marginal edge 64a of the flap and this angle is 45, the included angle between the slots therefore being The width of the slots is approximately equal to the thickness of the fibreboard employed in the side flaps, and the slots extend to points equidistant between the lower marginal edge 64a and the score line separating the flap from the end panel 59.

The side flap 62 has the general appearance of the usual rectangular flap of a regular slotted carton but with a triangular notch in each lateral edge. The notches thus form the ears 66 and 67. The notch which forms the ear 66 is somewhat in the form of an isosceles right triangle, a first portion of which defines the edge 6% of the fiap 62 and extends from the score line at the upper margin of flap 62 toward the lower marginal edge 62a at a 45 angle with respect to the score line. It extends in this direction to a point halfway between the lower marginal edge 62a and the upper edge of the flap 62 where the other side 620 of the triangle extends at 90 to the edge 62!) and continues to a point adjacent the edge 62a where it is clipped at 62d so that the ear 66 does not terminate in a point. The ear 67 is formed in the same way.

After the box blank is set up so that the wall forming panels define a rectangular polygon, the end flaps are turned inwardly on their score lines and upwardly so as to make acute angles with the end panels to which they are joined. During this inward and upward turning process, as soon as the end flaps have reached a position where they are in a plane perpendicular to the walls of the box, the inward and upward turning of the side flaps can begin. As soon as the side flaps have been turned up to a point where the ears thereof are aligned with the slots in the end flaps, the ears are allowed to enter the slots (FIG. 2) whereupon the flaps may be pushed back to a common plane perpendicular to the walls of the box. The box bottom is thereby closed and when viewed from the inside of the box will have the appearance shown in FIG. 3 and when viewed from the outside of the box will have the appearance shown in FIG. 4.

3 7 By having the slots begin at a point centrally locate and at the lower edge of the end flaps, and extend at 45 thereto and terminate approximately half-way between the lower edge and the score line of the flap, and by constructing the side flaps as described above, the maximum strength of the completed box bottom is obtained.

Where a particularly long box is to be employed, an additional strength factor is added by employing the constructionshown in FIGS. '5, 6, and 7. In these figures, the portions which may be the same as those in the preceding figures, are given the same reference numerals. The bottom forming flaps have a similar general appearance to those in the preceding figures. However, there are tabs 82 and '83 provided on the side flaps 84 and 86, respectively. While the distance between the flapdefining score line'87 and the lower marginal edge 84a of the flap 84 is approximately equal to one-half the Width of the end wall panels of the box, the distance from the score line 87 to'ithe lower marginal edge 82a of the tab 82 is substantially greater than this. The left-hand edge 82b of the Q tab 82 is immediately to the right of a vertical line 85 at the center of the flap. Similarly, the right-hand edge 83!) of the tab83 is just to the left of a vertical line 88 through the center of the flap 86. By so forming these tabs 82 and 83, when the bottom of the box has been formed in the manner described with respect to the first embodiment of the invention, the tabs '82 and 83 overlap the flaps 86 and 84, respectively, throughout a considerable portion of the distance between the ends of the box. These tabs thereby substantially enhance the strength of the bottom of the box.

It is .tobe noted also that'the end flaps 89 and 91 are constructed sot-hat the distance between the score lines therefor and the edges parallel to the score lines is equal to the distance between the score line 87 and the edge 82a of the tabt82. This makes .full use of the size of the box blank being used and adds to the strength of the bottom. The dimension between the edges 92 at the entrance to the slots'93rand 94 is made approximately twice the depth of the tab 82 measured between the margins 82a and 84a. This provides ample clearance between theedges and the tabs when the bottom of the box is closed.

From the foregoing description, it is believed apparent that the -self locking box constructed according to the present invention, is a substantial improvement over the boxes heretofore known and is well adapted to achieve the objects set out herein.

While the invention has been disclosed and described in some detail inthe drawings and foregoing description, they a'r'ei'to be considered'as illustrative and not restrictive in character, as other modifications may readily suggest themselves'to persons skilled in "this art and within the broad scope ofthe invention, reference being bad to the appendedclaims.

The invention claimed is:

1. A self locking box comprising: a pair of spaced parallel side Walls (56, 57); a pair of spaced parallel end walls (58, 59) joining said side walls and perpendicular to said side walls; a pair of end flaps (89, 91), each being turned inwardly from one of said end walls at the lower margin of the wall and each being of material integral with said end walls, each end flap having an inner marginal edge (89a) with a pair of slots 3, 94) diverging from a common origin adjacent said edge, said slots being oriented at 90 with respect to each other and eachslot being at .a 45 angle with respect to the marginal edge, both of saidslots extending to points between the said marginal edge (89a) of the flap and the end wall (59) to which it is-joined; and a pair of side flaps (34, 86), each of said side flaps lying in a plane common to that of the other side flap and perpendicular to said walls, each of said side flaps being turned inwardly from one of said side walls at the .lower margin of the wall and having an inner marginal edge (840) located at a distance from the wall (57) aproximately equal to one-half the width of one of said end walls (59), and each of said side flaps having a generally L-shaped lateral marginal edge with a first portion (84b) beginning at the lower margin of the side wall and extending at an angle of thereto to a place approximately one-half the distance between said side wall and said inner marginal edge of the side flap, and a second portion (84c) extending from said place at a 90 angle with respect to said first port-ion of the edge and continuing to a location adjacent one of said end walls and from said location continuing to the inner marginal edge (84a) of said side flap, a portion of the inner marginal edge of a side flap and said second portion of said notch edge thereby forming an ear (96), each of said side flaps thereby having two ears (96, 9 7) and each of the ears of said side flaps being received completely through one of the slots of said end flaps and overlying a portion of said end flaps, with the portions of said end fiaps between the slots thereof and the inner marginal edges thereof overlying portions of said side flaps, wherebycsaid flaps are interlocked completing the bottom of the box, each of said side flaps having a tab (82, 83) at the inner. marginal edge thereof and projecting away from the side wall :to which the'flap is attached and overlying a portion of vthe side flap attached to the opposite side wall, said tabs beginning at origins (82b, 83b) nearly equidistant between the end walls of said box and extending away fromcsaid origins toward opposite end walls of said box to permit an extensive-overlapping relationship between each of the tabs and a portion of the opposite side flap; and wherein the distance between the inner marginal edge (89a) of each end flap and the wall to which it is attached is approximately equal to the distance between the inner marginal edge (82a) of the said tab and-the side wall to'which the tab is attached, there being a space at the origin of said slotshcco-mmodating the said overlapping relationship of saidtabs.

2. A self locking box comprising: a pair of spaced parallel side walls; a pair of spaced parallel end walls joining said side walls and perpendicular to said side walls; a pair of end fiaps, each being turned inwardly from one of said end-walls at the lower margin of the-wall and each being of material integral with said end walls, each end flap having :an inner marginal edge with a pair of slots diverging from a common origin adjacent said edge, said slots'being oriented'at with respect to each other and each slot being at a 45 angle with respect to the marginal edge, both of said slots extending to points located substantially one-half the distance between the said marginal edge of the flap and the end wall to which it is joined; and a pair of side flaps, each of said side flaps lying in a plane common to that of the other side flap and perpendicular to said Walls, each of said side flaps beingturned inwardly from one of said side walls at the lower margin of the wall *and having an inner marginal edge located at a distance from the wall approximately equal to one-half the width of one of said end walls, and each of said side fiaps having a generally L-shaped lateral marginal edge with a first portion beginning at the lower margin of the side Wall and extending at an angle of 45 thereto to a place approximately one-half the distance between said side wall and said inner marginal edge of the side flap, and a second'portion extending from said place at a 90 angle with respect to said first portion of the edge and continuing to a location adjacent one of said end walls and from said location continuing to the inner marginal edge of said side flap, a portion of the inner marginal edge of a side flap and said second portion of said notch edge thereby forming an ear, each of said side .fiaps thereby having two ears and each of the ears of said side flaps being received completely through one of the slots of said end flaps and overlying a portion of said end flaps, with the portions of said end flaps between the slots thereof and the inner marginal edges thereof overlying portions of said side flaps, whereby 5 said flaps are interlocked completing the bottom of the box.

3. A self locking box comprising: a pair of spaced parallel side walls; a pair of spaced parallel end walls joining said side walls and perpendicular to said side walls; a pair of end flaps, each being turned inwardly from one of said end walls at the lower margin of the end wall, each end flap having an inner marginal edge with a pair of divergent slots both of said slots beginning at said edge and extending to points between the marginal edge of the flap and the end wall to which it is joined; and a pair of side flaps, each of said side flaps lying in a plane common to that of the other side flap and perpendicular to said walls, each of said side flaps being turned inwardly from one of said walls at the lower margin of the said side wall, each of said side flaps having an inner marginal edge, and each of said side flaps having two ears and each of the ears of said side flaps being received through one of the slots of said end flaps and overlying a portion of said end flaps, with the portions of said end flaps between the slots thereof and the inner ii marginal edges thereof overlying portions of said side flaps, whereby said flaps are interlocked completing the bottom of the box.

4. The box as set forth in claim 3 and wherein each of said side flaps has a tab at the inner marginal edge thereof and projecting away from the side wall to which the flap is attached and overlying a portion of the side flap attached to the opposite side wall, said tabs extending in said overlying relation a substantial distance parallel to said side walls and thereby strengthening the bottom of the box.

5. The box as set forth in claim 3 and wherein each flap of one of said pairs of flaps has a tab at the inner marginal edge thereof projecting away from the wall to which the flap is attached and overlying a portion of the flap attached to the opposite wall to strengthen the bottom of the box.

No references cited.

FRANKLIN T. GARRETT, Primary Examiner. 

1. A SELF LOCKING BOX COMPRISING: A PAIR OF SPACED PARALLEL SIDE WALLS (56,57); A PAIR OF SPACED PARALLEL END WALLS (58,59) JOINING SAID SIDE WALLS AND PERPENDICULAR TO SAID SIDE WALLS; A PAIR OF END FLAPS (89,91), EACH BEING TURNED INWARDLY FROM ONE OF SAID END WALLS AT THE LOWER MARGIN OF THE WALL AND EACH BEING OF MATERIAL INTEGRAL WITH SAID END WALLS, EACH END FLAP HAVING AN INNER MARGINAL EDGE (89A) WITH A PAIR OF SLOTS (93,94) DIVERGING FROM A COMMON ORIGIN ADJACENT SID EDGE, SAID SLOTS BEING ORIENTED AT 90* WITH RESPECT TO EACH OTHER AND EACH SLOT BEING AT A 45* ANGLE WITH RESPECT TO THE MARGINAL EDGE, BOTH OF SAID SLOTS EXTENDING TO POINTS BETWEEN THE SAID MARGINAL EDGE (89A) OF THE FLAP AND THE END WALL (59) TO WHICH IT IS JOINED; AND A PAIR OF SIDE FLAPS (84,86), EACH OF SAID SIDE FLAPS LYING IN A PLANE COMMON TO THAT OF THE OTHER SIDE FLAP AND PERPENDICULAR TO SAID WALLS EACH OF SAID SIDE FLAPS BEING TURNED INWARDLY FROM ONE OF SAID EACH WALLS AT THE LOWER MARGIN OF THE WALL AND HAVING AN INNER MARGINAL EDGE (84A) LOCATED AT A DISTANCE FROM THE WALL (57) APROXIMATELY EQUAL TO ONE-HALF THE WIDTH OF ONE OF SAID END WALLS (59), AND EACH OF SAID SIDE FLAPS HAVING A GENERALLY L-SHAPED LATERAL MARGIN EDGE WITH A FIRST PORTION (84B) BEGINNING AT THE LOWER MARGIN OF THE SIDE WALL AND EXTENDING AT AN ANGLE OF 45* THEREOT TO A PLACE APPROXIMATELY ONE-HALF THE DISTANCE BETWEEN SAID SIDE WALL AND SAID INNER MARGINAL EDGE OF THE SIDE FLAP, AND A SECOND PORTION (84C) EXTENDING FROM SAID PLACE AT A 90* ANGLE WITH RESPECT TO SAID FIRST PORTION OF THE EDGE AND CONTINUING TO A LOCATION ADJACENT ONE OF SAID END WALLS AND FROM SAID LOCATION CONTINUING TO THE INNER MARGINAL EDGE (84A) OF SAID SIDE FLAP, A PORTION OF THE INNER MARGINAL EDGE OF A SIDE FLAP AND SAID SECOND PORTION OF SAID NOTCH EDGE THEREBY FORMING AN EAR (96), EACH OF SAID SIDE FLAPS THEREBY HAVING TWO EARS (96,97) AND EACH OF THE EARS OF SAID SIDE FLAPS BEING RECEIVED COMPLETELY THROUGH ONE OF THE SLOTS OF SAID END FLAPS AND OVERLYING A PORTION OF SAID END FLAPS, WITH THE PORTIONS OF SAID END FLAPS BETWEEN THE SLOTS THEREOF AND THE INNER MARGINAL EDGES THEROF OVERLYING PORTIONS OF SAID SIDE FLAPS, WHEREBY SAID FLAPS ARE INTERLOCKED COMPLETING THE BOTTOM OF THE BOX, EACH OF SAID SIDE FLAPS HAVING A TAB (82,83) AT THE INNER MARGINAL EDGE THEREOF AND PROJECTING AWAY FROM THE SIDE WALL TO WHICH THE FLAP IS ATTACHED AND OVERLYING A PORTION OF THE SIDE FLAP ATTACHED TO THE OPPOSITE SIDE WALL, SAID TABS BEGINNING AT ORIGINS (82B,83B) NEARLY EQUIDISTANT BETWEEN THE END WALLS OF SAID BOX AND EXTENDING AWAY FROM SAID ORIGINS TOWARD OPPOSITE END WALLS OF SAID BOX TO PERMIT AN EXTENSIVE OVERLAPPING RELATIONSHIP BETWEEN EACH OF THE TABS AND A PORTION OF THE OPPOSITE SIDE FLAPS; AND WHEREIN THE DISTANCE BETWEEN THE INNER MARGINAL EDGE (89B) OF EACH END FLAP AND THE WALL TO WHICH IT IS ATTACHED IS APPROXIMATELY EQUAL TO THE DISTANCE BETWEEN THE INNER MARGINAL EDGE (82A) OF THE SAID TAB AND THE SIDE WALL TO WHICH THE TAB IS ATTACHED, THERE BEING A SPACE AT THE ORIGIN OF SAID SLOTS ACCOMMODATING THE SAID OVERLAPPING RELATIONSHIP OF SAID TABS. 